Large Eddy/Reynolds-Averaged Navier-Stokes Simulations of Scramjet Combustor Flow Fields

Edwards, Jack R.; Potturi, Amarnatha Sarma; Fulton, Jesse

doi:10.2514/6.2012-4262

Cited by 18 publications

(10 citation statements)

References 14 publications

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“…From the literature, the most preferred modeling cases are the HyperShot I&II [3][4][5][6][7][8][9][10] and SCHOLAR [11][12][13][14][15][16], due a large degree to their relative complete data on experimental setup and measurements 2 American Institute of Aeronautics and Astronautics for model validation. Simulations based on the experimental cases tested on some other scramjet combustor facilities, such as the DLR scramjet combustor [17,18], the University of Virginia's Supersonic Combustion Facility (SCF) [18][19][20][21] and the CUBRC Combustion Duct [22], are also growing vigorously. To date, promising work on modeling those experimental cases is still under way to validate the physical models and shock/turbulence capturing algorithms for supersonic combustion, as well as to improve the computational efficiency [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Full-scale Detached Eddy Simulation of kerosene fueled scramjet combustor based on skeletal mechanism

Yao¹,

Wang²,

Lu³

et al. 2015

20th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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Large Eddy Simulation (LES) of kerosene fueled scramjet combustor is generally scare in the literature, due mainly to the formidable computational cost arisen by complex kerosene mechanism. In this study, the skeletal reduction of a detailed reaction mechanism (2185 species/8217 steps) of aviation kerosene is conducted using directed relation graph with error propagation and sensitivity analysis (DRGEPSA) method, resulting a skeletal mechanism consisting of 39 species/153 elemental reactions for China Daqing RP-3 aviation kerosene. The comparisons of adiabatic flame temperature, total heat release, ignition delay and laminar flame speed predicted by the skeletal mechanism show an overall good accordance with the original detailed reaction mechanism. Then a three-dimensional Detached Eddy Simulation (DES) modeling based on the skeletal kerosene mechanism is employed for the numerical analysis of a full-scale scramjet combustor, which has been experimentally tested in a long-time direct connect supersonic combustion test platform (abbreviated as DTZ) assembled in Chinese Academy of Sciences (CAS). Pressure and heat flux measurement systems are attached to the combustor assembly to monitor the real-time combustion performance and provide validation data for the numerical modeling. Three cases with fuel equivalence ratios from 0.8, 1.0 to 1.2 and the same crossflow conditions at Mach 2.0 are modeled. The time-averaged static pressure and heat flux are in generally good agreement with the experiment with the peak heat flux slightly underpredicted. The instantaneous and/or time-averaged pressure, momentum, temperature and turbulence fields, which are difficult to be measured, are analyzed to reveal the main flow and combustion physics, especially those related to the flame distribution and holding. The combustion is identified as in ramjet mode for the investigated cases. With the increasing of fuel equivalence ratio, the shock train propagates upstream in the isolator and the interaction between the upstream and downstream combustion assumes different patterns.

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Section: Introductionmentioning

confidence: 99%

Full-scale Detached Eddy Simulation of kerosene fueled scramjet combustor based on skeletal mechanism

Yao¹,

Wang²,

Lu³

et al. 2015

20th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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“…In previous studies using Configuration A [5], a nine-species Jachimowski model was used [12], and in a more recent work [6], a study was conducted comparing the Jachimowski results with another reaction model by O'Connaire [13]. Parallel to this work was an effort to capture the effects of combustor inflow turbulence by introducing artificial fluctuations at the inflow plane and sustaining them using a turbulence recycling / rescaling technique (described later in more detail).…”

Section: Methodsmentioning

confidence: 99%

“…The resulting flux splitting scheme has been named the low-dissipation TVD scheme (LD-TVD) and further details of its implementation in this project can be found in [6]. The REACTMB code operates on the assumption of a mixture of thermally perfect gases.…”

Section: Methodsmentioning

confidence: 99%

“…The assumption used for this paper is that of fully 'laminar' chemistry, that is, no effects of SGS turbulence is taken into account when evaluating species production / depletion rates. In [6], work was done to evaluate Gaussian-quadrature and randomized-quadrature reconstructive SGS closures for chemical kinetics on Configuration A of the UVa combustor. It was found that these two closures did not bring the solution closer to experimental CARS measurements of temperatures in the combustor while they significantly increased computational expense.…”

Section: Methodsmentioning

confidence: 99%

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Continued Hybrid LES /RANS Simulation of a Hypersonic Dual-Mode Scramjet Combustor

Fulton

Edwards

Hassan

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Results of an ongoing hybrid LES / RANS simulation of the experimental ScramjetCombustion Facility located at the University of Virginia are discussed, using an updated combustor flowpath named Configuration C. This new configuration includes a long isolator section and a region of constant cross-sectional area in the otherwise divergent combustor / extender section. Additional refinements have been made to the numerical simulations to bring closer agreement to actual facility operation, including thermal non-uniformity and thermal non-equilibrium of the air supply and a forced turbulent profile at the simulation's inflow boundary using recycling / rescaling methods. As in previous studies, NC State's REACTMB finite-volume solver is employed which uses Edwards' LDFSS inviscid fluxsplitting scheme and Menter's BSL turbulence closure for the RANS portion of the LES / RANS simulations. A different H 2 -O 2 kinetics model by Burke was incorporated which provided better flameholding capability after inflow turbulence was introduced in the simulations. Simulations were performed for the equivalence ratios of 0.18 and 0.49. Instantaneous and time-averaged results for each simulation are compared with coherent anti-Stokes Raman spectroscopy (CARS), hydroxyl radical planar laser-induced fluorescence (OH-PLIF), and stereoscopic particle image velocimetry (SPIV) non-intrusive measurements made on the facility, as well as static pressure data also obtained. These comparisons indicate that the numerical results are in generally good agreement with measurements; however, it was found that the simulations consistently over-predicted the flame temperatures and level of turbulent fluctuations in the flame-holding area just downstream of the fuel injector. The simulations conducted at the highest equivalence ratio captured the unstart of the pre-combustion shock train which was experimentally observed. Although a final stable shock-train position could not be determined in time for this paper, current predictions are in generally good agreement with experimental CARS and wallpressure measurements.

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“…The hybrid LES∕RANS approach developed at North Carolina State University (NC State) has been used extensively to study internal flows for scramjets, supersonic flow over flat plates and compression corners, and shock/boundary-layer interactions [16][17][18][19][20][21][22]. However, these methods have not been previously validated for reentry-type problems.…”

Section: Introductionmentioning

confidence: 99%

Mach 6 Wake Flow Simulations Using a Large-Eddy Simulation/Reynolds-Averaged Navier–Stokes Model

Salazar

Edwards

2014

Journal of Spacecraft and Rockets

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A hybrid large-eddy simulation/Reynolds-averaged Navier-Stokes turbulence model is used to simulate the Mach 6 flow around a scaled model similar to NASA's Orion multipurpose crew vehicle. The results for surface pressure and heat transfer are compared with experimental data from previous base flow experiments conducted at the CalspanUniversity at Buffalo Research Center. Using the highest Reynolds number test case (11 × 10 6 based on capsule diameter), different numerical aspects of the hybrid approach are addressed, such as use of a low-dissipation scheme, a modification to the eddy-viscosity blending function, time-averaging results, filtering computational results, and sensitivity to grid resolution. In addition, results are compared with Reynolds-Averaged Navier-Stokes using Menter's two-equation baseline model and to detached-eddy simulation predictions. By introducing a new modification to the blending from Reynolds-averaged Navier-Stokes to large-eddy simulation within boundary layers, very good agreement with the experiment is obtained in regions where the boundary-layer grid spacing is too coarse for large-eddy simulation. The findings show that the high-fidelity schemes produce results that agree much better with the experimental data than Reynolds-averaged Navier-Stokes methods, which tend to underpredict base pressures and overpredict heat fluxes. The overall accuracy of each scheme is evaluated using a normalized root mean square error in different regions of the flow, and the analysis shows that, in separated regions, the integrated error is over 120% using a Reynolds-averaged Navier-Stokes model, and 30-50% using the higher fidelity schemes. Additionally, the hybrid methodology presented is further validated by considering a lower Reynolds number (6 × 10 6 ), where the flow is nominally transitional, and very accurate heat transfer predictions are also obtained. NomenclatureC M = hybrid large-eddy simulation/Reynolds-averaged Navier-Stokes model constant, 0.06 D = capsule diameter, m d = distance from the nearest wall, m gl out = blending correction function k, k R = turbulence, resolved kinetic energy, m 2 ∕s 2 l inn , l out = inner, outer boundary-layer length scale, m M ∞ = freestream Mach number Re D = Reynolds number based on capsule diameter S = vorticity tensor, 1∕s T wall = wall temperature, K T ∞ = freestream temperature, K t = time, s U ∞ = freestream velocity, m∕s u i = velocity component, m∕ŝũ = resolvable-scale Favre-averaged velocity component, m∕s u = Favre-averaged velocity component, m∕s Γ = large-eddy simulation/Reynolds-averaged NavierStokes blending function Δ = cell volume, m 3 Δ max = maximum grid spacing over the three coordinate directions, m ϵ = turbulent kinetic energy dissipation rate, m 2 ∕s 3 κ = von Kármán constant λ = length scale ratio for blending function μ μ T= molecular, turbulent viscosity, Pa · s ν = kinematic viscosity, m 2 ∕s ν T = kinematic eddy viscosity, m 2 ∕s ν T;SGS = subgrid kinematic eddy viscosity, m 2 ∕s ρ = density, kg∕m 3 ρ ∞ = freestream density...

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Large Eddy/Reynolds-Averaged Navier-Stokes Simulations of Scramjet Combustor Flow Fields

Cited by 18 publications

References 14 publications

Full-scale Detached Eddy Simulation of kerosene fueled scramjet combustor based on skeletal mechanism

Full-scale Detached Eddy Simulation of kerosene fueled scramjet combustor based on skeletal mechanism

Continued Hybrid LES /RANS Simulation of a Hypersonic Dual-Mode Scramjet Combustor

Mach 6 Wake Flow Simulations Using a Large-Eddy Simulation/Reynolds-Averaged Navier–Stokes Model

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